1. Field of the Invention
The present invention relates to modulation systems and more particularly to digitally compensated modulation systems that provide a single modulation input line with flat frequency response to DC.
2. Description of the Prior Art
There are several digitally compensated modulation systems for frequency synthesizers available in the prior art. All of these modulation systems, however, require complicated connections between modules requiring modulation. Such modules include audio processors, encryption devices, modems, etc.
A typical digitally compensated modulation system of the prior art is shown in FIG. 1. A problem with this implementation is that input signal frequencies below the synthesizer loop bandwidth are rejected.
It is an object of the present invention to simplify connections between these modules, especially when low frequency modulation (below the synthesizer loop bandwidth) or NRZ (non-return-to-zero) schemes are used.
It is another object of the present invention to eliminate components and adjustments by integration of modulation system functions.